Fuse cartridge



Sept 18 1934 F. BRANDT FUSE CARTRIDGE mea oct. 2s, 1932 i wlllllllw.

Patented Sept. 18, 1.934

UNITED sTATas FUSE CARTRIDGE Fritz Brandt, Biesenthal, Germany, assigner to Siemens & Halske Aktiengesellschaft, Siemensstadt, near Berlin, Germany Application October 28, 1932, Serial No. 639,956 In Germany December 1, 1931 The present invention relates to a fuse of the type generally used in telephone systems and has for its object to produce such a .fuse having a particularly favorable design. Fuses of the type in which re-soldering is eliminated and which are restored to an operable condition simply by conversion or replacement are well known in the art. The design of such fuses, however, is defectivein that they have to be entirely removed from the fuse strip in order to be restored to an operable condition, and the portion to be replaced or converted is inaccessibly placed within the fuse cartridge.

This defect is eliminated in the present invention by using a fuse cartridge in two parts, one part of which comprises the heating .winding together with its soldering pin, which isdetachably connected to the other part containing the spring which inuences the soldered pin. In order to restore such a fuse to an operable condtion the portion containing the compression spring may be left in the fuse strip and only the part comprising the heating winding together with its soldered pin need be detached, rotated 180 and then replaced. The detachable portion of the fuse, therefore, is readily accessible and fitted in a very simple manner.

The subject matter of the present invention is described in detail below and illustrated in the accompanying drawing in which- Fig. 1 shows a cross section of the fuse according to the present invention in operated position;

Fig. 2 fs a full view of the fuse in normal position; and

Fig. 3 is a view of a part of the fuse according to the present invention.

The fuse consists of a fuse holder comprising a sleeve 1 containing a spring 2 which presses upon a plunger 3 arranged within the sleeve 1. This sleeve 1 in its upper part is provided with an enlarged portion 4 into which a heating winding or coil 5 is detachably fitted by means of pins 6 in the manner of a bayonet fastening. Within the coil 5 a pin 7 is fixed in the usual manner by means of readily fusible solder. When the coil 5 is inserted in the enlarged portion 4 of the fuse holder, the pin 7 presses the plunger 3 downwardly against the force of the spring 2. The lower portion 1 of the sleeve is provided with a projection 8 which holds the fuse in position in the fuse strip. The plunger in turn presses against contact springs (not shown) over which' extends the circuit in which the fuse is to operate. The electrical circuit follows a path extending from the contact springs mentioned, through plunger 3 which is insulated at the top and bottom from the sleeve 1, pin f7, the solder and the spool to which one end of the winding 5 is fastened, through winding 5 to its other end Awhich is fastened to the. outside casing of the heat coil and insulated from the spool containing winding 5 by the spool heads, enlarged portion 4 and sleeve 1, to the fuse strip which holds the fuse assembly in position.

If the coil body 5 is excessively heated, the pin 'I under the pressure of the plunger 3 is pressed outwards through the coil centre whereupon the connection between the contact springs (not shown) and the plunger 3 is broken. The coil then cools down and the solder with which the pin 7 is xed solidifies automatically, thus fixing the pin 7 in the usual manner.

In order to restore the fuse toY an operable condition the coil body 5 is removed from the upper portion of the sleeve 4 by sliding the pins 6 from their bayonet slots, rotating 180 and then replacing it in its original position, whereupon the plunger 3 is again depressed as before. The fuse is so constructed that it can be used everywhere in place of the prior known re-soldering fuses without altering the fuse strips in any Way. The accessibility of the detachable coil body considerably simplifies its manipulation. The construction has the additional advantage that the detachable portion contains just those components which are subject to the greatest wear and tear (the coil burning out or the solder getting lost) so that even if the fuse has to be repaired this is a Very simple operation.

What is claimed is:

1` In combination, a reversible fuse cartridge containing a heating winding and a soldered pin released thereby, a holder for the cartridge having a spring plunger for moving the pin when released, bayonet slots in the holder and bayonets on the cartridge for retaining the cartridge in place and retaining the pin against the plunger, said cartridge retained solely by the bayonet and slots when either end of the cartridge is inserted in the holder.

2. In combination with a fuse cartridge containing a soldered pin movable when the solder is fused, and a heating winding for fusing the A FRITZ BRANDT. 

